نتایج جستجو برای: pelagic
تعداد نتایج: 5978 فیلتر نتایج به سال:
It has been speculated that some deep-sea fishes can display large vertical migrations and likely doing so to explore the full suite of benthopelagic food resources, especially the pelagic organisms of the deep scattering layer (DSL). This would help explain the success of fishes residing at seamounts and the increased biodiversity found in these features of the open ocean. We combined active p...
Fish larvae require high densities of appropriately sized prey items for their survival and recruitment. It has been widely assumed that inundated floodplains are the major source of high densities of prey in floodplain rivers. This study examined the density and distribution of both pelagic and epibenthic meiofauna in a range of potential larval fish nursery habitats within the main channel of...
Marine food webs are important links between Hg in the environment and human exposure via consumption of fish. Estuaries contain sediment repositories of Hg and are also critical habitat for marine fish and shellfish species consumed by humans. MeHg biotransfers from sites of production in estuarine sediments to higher trophic levels via both benthic and pelagic pathways. In this study, we inve...
Juvenile loggerhead turtles (Caretta caretta) have recently been documented in the vicinity of Baja California and thousands of these animals have been captured in oceanic fisheries of the North Pacific. The presence of loggerhead turtles in the central and eastern North Pacific is a prominent enigma in marine turtle distribution because the nearest documented nesting concentrations for this sp...
This is the first attempt to compile a comprehensive and updated species list for Hydrozoa in the Arctic, encompassing both hydroid and medusa stages and including Siphonophorae. We address the hypothesis that the presence of a pelagic stage (holo- or meroplanktonic) was not necessary to successfully recolonize the Arctic by Hydrozoa after the Last Glacial Maximum. Presence-absence data of Hydr...
Large pelagic fishes are top predators inhabiting the water column of the tropical and subtropical Pacific Ocean. They are highly migratory organisms, and for Ecuadorian fisheries, they also represent important economic resources. We sampled 4 shark species, Prionace glauca, Isurus oxyrinchus, Carcharhinus falciformis and Alopias pelagicus, and 3 billfish species, Xiphias gladius, Istiophorus p...
Most species-rich lineages of aquatic organisms have undergone divergence between forms that feed from the substrate (benthic feeding) and forms that feed from the water column (pelagic feeding). Changes in trophic niche are frequently accompanied by changes in skull mechanics, and multiple fish lineages have evolved highly specialized biomechanical configurations that allow them to protrude th...
The input of mercury (Hg) to ecosystems is estimated to have increased two- to fivefold during the industrial era, and Hg accumulates in aquatic biota as neurotoxic methylmercury (MeHg). Escalating anthropogenic land use and climate change are expected to alter the input rates of terrestrial natural organic matter (NOM) and nutrients to aquatic ecosystems. For example, climate change has been p...
Thecosome pteropods (pelagic mollusks) can play a key role in the food web of various marine ecosystems. They are a food source for zooplankton or higher predators such as fishes, whales and birds that is particularly important in high latitude areas. Since they harbor a highly soluble aragonitic shell, they could be very sensitive to ocean acidification driven by the increase of anthropogenic ...
Rebecca L. Lewison*, Sloan A. Freeman and Larry B. Crowder Duke University Marine Laboratory, Nicholas School of the Environment and Earth Sciences, 135 Duke Marine Lab Road, Beaufort, NC 28516, USA *Correspondence: E-mail: [email protected] Abstract The depletion of fish stocks from global fisheries has been a long-standing concern. More recently, incidental catch of non-target (termed ...
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